/*================================================

General

================================================*/

* {
  box-sizing: border-box;
}

html,
body {
  background-color: #000;
  height: 100%;
}

body {
  background: #222;
  background: -webkit-radial-gradient(#333, #111);
  background: radial-gradient(#333, #111);
  background-position: center center;
  background-repeat: no-repeat;
  background-size: cover;
  color: #fff;
  font: 100%/1.5 sans-serif;
  overflow: hidden;
}

/*================================================

Score

================================================*/

.score {
  color: rgba(255, 255, 255, 0.5);
  font-size: 16px;
  font-weight: bold;
  padding-top: 5px;
  text-align: center;
}

/*================================================

Stage

================================================*/

.stage {
  bottom: 0;
  left: 0;
  margin: auto;
  position: absolute;
  right: 0;
  top: 0;
  z-index: 2;
}

/*================================================

Tiles

================================================*/

.tile {
  background: rgba(0, 0, 0, 0.15);
  position: absolute;
  -webkit-transition-property:
    background,
    box-shadow,
    opacity,
    -webkit-transform
  ;
          transition-property:
    background,
    box-shadow,
    opacity,
    transform
  ;
  -webkit-transform: translateZ(0);
          transform: translateZ(0);
  -webkit-transition-duration: 3000ms;
          transition-duration: 3000ms;
}

.tile:before {
  bottom: 0;
  content: '';
  height: 0;
  left: 0;
  margin: auto;
  opacity: 0;
  position: absolute;
  right: 0;
  top: 0;
  width: 0;
  -webkit-transition: opacity 300ms;
          transition: opacity 300ms;
}

.tile.path:before {
  opacity: 1;
}

.tile.up:before {
  border-bottom: 4px inset rgba(255, 255, 255, 0.15);
  border-left: 4px solid transparent;
  border-right: 4px solid transparent;
}

.tile.down:before {
  border-top: 4px inset rgba(255, 255, 255, 0.15);
  border-left: 4px solid transparent;
  border-right: 4px solid transparent;
}

.tile.left:before { 
  border-right: 4px inset rgba(255, 255, 255, 0.15);
  border-top: 4px solid transparent;
  border-bottom: 4px solid transparent;
}

.tile.right:before { 
  border-left: 4px inset rgba(255, 255, 255, 0.15);
  border-top: 4px solid transparent;
  border-bottom: 4px solid transparent;
}

@media (max-width: 900px), (max-height: 900px) {
  .tile.up:before,
  .tile.down:before,
  .tile.left:before,
  .tile.right:before {
    border-width: 3px;
  }
}

@media (max-width: 500px), (max-height: 500px) {
  .tile.up:before,
  .tile.down:before,
  .tile.left:before,
  .tile.right:before {
    border-width: 2px;
  }
}

.tile.pressed {
  background: rgba(0, 0, 0, 0.3);
  box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.6);
  -webkit-transition-duration: 0ms;
          transition-duration: 0ms;
}